The Climate Book

The water cycle is the transference of water from the atmosphere to the ground and back again. Water evaporates from oceans, plants, and the ground, where it condenses to form clouds. Liquid or solid water is then released as precipitation, falling into waterways or on land. Some water seeps through the ground to form aquifers. The water cycle and the Earth’s climate are inextricably linked. Warming temperatures are increasing the rate of evaporation and precipitation, leaving some areas in drought and some at risk of heavy storms and flooding.

A mass extinction occurs when a large percentage of living species go extinct within a short period of time. There have been five mass extinctions on Earth, each of which are correlated with disruptions to the carbon cycle. Scientists suggest that human activity and climate change are causing a sixth mass extinction event.

Tonnes is a metric weight classification. One tonne is equivalent to 1,000 kg or to 2,200 pounds. A gigatonne is one billion metric tons, or approximately 2.2 trillion pounds. The metric tonnes and gigatonnes are used to discuss the levels of greenhouses gases, namely CO₂ that have been released into the atmosphere.

A carbon sink is a natural area, such as an ocean, forest, or grassland, that absorbs carbon from the atmosphere and stores it in plant material or the soil. Carbon sinks can help lower the levels of carbon dioxide from the atmosphere after emissions are stopped. Some carbon sinks are man-made, such as forests established by planting trees to offset carbon emissions. Carbon sinks alone cannot limit climate change, as carbon dioxide is accumulative, meaning the amount in the atmosphere will continue to grow if emissions continue.

Tipping points occur when a certain threshold is crossed creating a feedback loop, or self-perpetuating conditions. For instance, ice is reflective and deflects heat, while the dark, bare ground absorbs heat; once ice coverage is so low that it passes it’s tipping point, the heat absorbed by the bare ground will hasten warming, thus increasing the speed at which the ice melts, which then leads to even more heat absorption and faster melting. Because of the complexity of climate, scientists do not have accurate information regarding tipping points.

Colonialism occurs when a nation invades or acquires control over another country. Colonial settlers occupy acquired lands, often killing or displacing the Indigenous inhabitants, and they exploit the land for economic gains. Colonialism is still being practiced in many parts of the world, such as the colonial behavior exhibited in northern Sweden against the people in Sápmi discussed in 3.14.

Geoengineering, also called climate engineering, refers to the process of interfering with the atmosphere and Earth systems in a way that alters climate patterns. Geoengineering practices include the removal of carbon from the atmosphere—called drawdown technology—and the reflection of sunlight back into space, so that less solar heat penetrates the atmosphere. Contributors to The Climate Book argue that geoengineering is unsafe, as it may degrade the environment and perpetuate inequality. It also inhibits climate action by suggesting industrialized nations do not have to reduce their consumption.